Gemstones and Pearls

Gemstone Education

HAY Diamond sources all types of gemstones from the most reputable and trusted Gem merchants in the world.

There are five essential characteristics of gemstone quality and understanding these characteristics will enable you to shop with confidence. Get in touch with us to discuss your gemstone needs.



The highest quality and most desirable gemstones are usually the ones with the most intense colour saturation, a deep tone and purity of hue. Colour is generally the most important aspect of a gemstone as this determines how a gemstone will look. Because of the importance placed in colour the vast majority of stones on the market today are treated in some form to enhance the original colour. HAY Diamond
sell both natural and treated gemstones.



Like diamonds almost all gemstones contain inclusions and finding a flawless gemstone is extremely rare. Do not be daunted with buying a gemstone with some inclusions as we will only source gemstones that are eye clean.


Shape or Cut

Gemstones differ to diamonds in that they are generally cut to maximize the colour and not sparkle. There is no ideal cut range for a typical gemstone. Gemstones that have a higher saturated colour will usually be cut more shallow to allow more light through the gemstone, while a gemstone with a lighter saturation will usually be cut deeper to maximize the colour.



Most gemstones on the market are classified by diameter or dimensions rather than carat weight. This is due to gemstones having different densities so even though five different gemstones might have the same carat weight and cut, the actual sizes can differ. While the top view dimensions are important to get a gauge on how large the stone will look, the depth is also important as it is usually deeper than a typical diamond and you may need to make/buy a setting that can accommodate a deeper stone.



The vast majority of gemstones available today have been treated in some form. Natural untreated stones usually have exceptional Heat treatments to enhance colour is the most common while the other common treatment includes clarity enhancements.


Pearl Education

Pearls have always been one of the most sought after items for jewellery and with the different options available today it is important to understand what the differences are.

The vast majority of pearls on the market today are Cultured Pearls that have been grown by suppliers under controlled conditions. Natural pearls are now very rare. To make a cultured pearl a tiny bead is implanted by hand into an oyster and this is gradually coated over time in layers of nacre. Nacre is what gives pearls their wondrous colour and luster.

Types of pearls

There are four main types of pearls today.

  • South Sea Pearls
  • Akoya Pearls
  • Tahitian Pearls
  • Freshwater Pearls



There are many different colours that pearls come in. The most common colours are white, cream, yellow, pink, silver and black. Many pearls also have an overtone of a different colour when viewed under certain lighting conditions.



Generally the better the shine (luster) of a pearl, the more valuable and desirable the pearl is. Larger pearls generally have better luster as they have more nacre which is what gives the pearl its luster.



While most people associate pearls with a round shape, there are many other shapes. Round pearls are the rarest and most in demand, however large high luster baroque pearls are also known to be very valuable.



Pearls come in a variety of sizes and the type of pearl usually determines what size they come in. Freshwater pearls are generally the smallest ranging in size between 3 – 7mm on average. South Sea and Tahitian pearls are the largest growing up to over 14mm.



Pearls are very different to diamonds and gemstones and require different methods to clean and maintain. Wearing pearls often actually helps care for them as the body oils keep the pearls looking lustrous.